Human sperm displays rapid responses to diet.

The global rise in obesity and steady decline in sperm quality are two alarming trends that have emerged during recent decades. In parallel, evidence from model organisms shows that paternal diet can affect offspring metabolic health in a process involving sperm tRNA-derived small RNA (tsRNA). Here, we report that human sperm are acutely sensitive to nutrient flux, both in terms of sperm motility and changes in sperm tsRNA.

High-Affinity Sites Form an Interaction Network to Facilitate Spreading of the MSL Complex across the X Chromosome in Drosophila.

Dosage compensation mechanisms provide a paradigm to study the contribution of chromosomal conformation toward targeting and spreading of epigenetic regulators over a specific chromosome. By using Hi-C and 4C analyses, we show that high-affinity sites (HAS), landing platforms of the male-specific lethal (MSL) complex, are enriched around topologically associating domain (TAD) boundaries on the X chromosome and harbor more long-range contacts in a sex-independent manner. Ectopically expressed roX1 and roX2 RNAs target HAS on the X chromosome in trans and, via spatial proximity, induce spreading of the MSL complex in cis, leading to increased expression of neighboring autosomal genes.

Generation of reporter plasmids containing defined base modifications in the DNA strand of choice.

Physiological effects of DNA bases other than A, G, C, and T as well as ways of removal of such bases from genomes are studied intensely. Methods for targeted insertion of modified bases into DNA, therefore, are highly demanded in the fields of DNA repair and epigenetics. This article describes efficient procedures for incorporation of modified DNA bases into a plasmid-borne enhanced green fluorescent protein (EGFP) gene.

Mouse CSB protein is important for gene expression in the presence of a single-strand break in the non-transcribed DNA strand.

CSB protein is required for strand-specific repair of bulky DNA lesions in transcribed genes and mediates transcription recovery after exposure to DNA-damaging agents. We enzymatically generated DNA single-strand breaks (SSBs) with 3'-OH and 5'-phosphate termini in defined positions of a plasmid-borne gene and measured their effect on transcription in cell lines with different statuses of the Csb gene. A single SSB in the transcribed region of the gene caused significant decrease of gene expression.